The present invention relates broadly to an antiskid system, and in particular to an adaptive skid detector threshold apparatus for antiskid circuits.
At the present time, the conditions under which an aircraft may land are considerably more severe than has been possible in the past. This is largely due to the rapid and great advances that have been achieved in the state of the art for all-weather landing systems. The achievements, however, have created the need for a reliable means to effectively control the stopping of a variety of size aircraft under a host of varying severe runway conditions. Thus, it is plain that some form of antiskid system is required to insure a high level of safety in aircraft landing operations.
A shortcoming of the prior art antiskid braking systems has been the fixed deceleration threshold setting in the skid detector. On dry runways, wheel lockup rates will normally occur at a faster rate than under slippery conditions, thus requiring that the skid detector threshold be set to a compromise wheel deceleration rate between the extremes of operating conditions which are encountered. As a result, some braking performance is lost because deeper wheel skids are encountered on slippery runways.
The present invention is an improvement over an antiskid circuit of the type as proposed in the patent application of Henrik H. Straub, Ser. No. 566,158 for a fluidic antiskid circuit, now U.S. Pat. No. 3,985,398 issued Oct. 12, 1976.